中国海相早三叠世弓鲛鱼类(软骨鱼类)的首次报道——华南二叠系—三叠系界线上下鱼类序列研究之一

广西田东县作登下三叠统罗楼组产出弓鲛鱼类 :作登弓鲛Hyboduszuodengensis(Yangetal.)、乐氏弓鲛H .yohi (Yangetal.)和田东多尖齿鱼 (新种 )Polyacrodustiandongensissp .nov .,其中前二种化石以前曾被作为牙形类报道。这是弓鲛鱼类在中国海相早三叠世的首次报道。另外 ,本组还产出属种未定的硬骨鱼类化石 (Osteichthyesgen .etsp .indet.)。建立了我国海相早三叠世第一个鱼类带化石 ,作登弓鲛—乐氏弓鲛组合带 (Hyboduszuodengensis H .yohiAZ) ;伴生的有Neospathodushomeri N .triangularis牙形类带化石 ,该带化石延续的时限为奥伦尼克阶 (Olenekian)司帕斯期 (Spathian)早期。

EARLY TRIASSIC HYBODONTOIDEA FROM TIANDONG OFGUANGXI,CHINA--First Report on the Fish Sequence Study Near the Permian Triassic Boundary in South China

The materials dealt with in this paper were collected from the Luolou Formation of Zuodeng area, Tiandong County of Guangxi Zhuang Autonomous Region, China (Figs. 1,2). They include three hybodontoid species: Hybodus zuodengensis (Yang et al., 1984), H. yohi (Yang et al., 1984) and Polyacrodus tiandongensis sp. nov., and an indeterminate osteichthyan fish. The two species of Hybodus were initially identified as conodonts-Pachycladina zuodengensis and Pseudogondalella yohi by Yang et al. in 1984.This is the first report on the occurrence of marine Early Triassic Hybodontoidea in China. With the reassignment and new discovery of these fishes, a fish assemblage (Hybodus zuodengensis H. yohi Zone) is established, which is the only Triassic fish zonation in China. The age of this zonation is Early Triassic (early Spathian of Olenekian Stage) for it makes its appearance just in the conodont Neospathodus homeri N. triangularis Zone.